1. Technical Field
The present invention relates to an ejection inspection method and a liquid ejection device.
2. Related Art
As a liquid droplet ejection head provided with a liquid ejection nozzle which can eject liquid in a liquid droplet state, an inkjet recording head used for an image recording device (liquid ejection device) such as a printer has been put into practical use. Further, these days, application to various devices has been considered making use of the characteristics that a very small amount of liquid can be ejected with good accuracy. For example, a color material ejection head used for manufacturing a color filter such as a liquid crystal display, or an electrode material ejection head used for forming an electrode for an organic EL (Electro Luminescence) display, an FED (Field Emission Display), or the like has been proposed.
In general, this type of liquid droplet ejection head has a plurality of nozzle openings, and liquid droplets are ejected from each of the nozzle openings. Therefore, liquid is exposed to the atmosphere in the nozzle opening, and a solvent component of the liquid evaporates through meniscus (free surface of liquid exposed in the nozzle opening). Evaporation of the solvent component causes increase in the concentration of other components which constitute the liquid, which results in deviation of the flight of liquid droplets, clogging in the nozzle opening, or the like. Further, if a nozzle opening is put into a clogging state, the nozzle opening cannot eject liquid droplets, which might cause various problems. For example, in a recording head, dots are not allowed to land onto correct landing positions on a recording medium, which might cause deterioration in the image quality, or the ejection amount of liquid is shifted from a proper amount, which might cause a situation in which desired characteristics cannot be obtained.
It is important to detect whether or not a defective dot occurs in order to achieve desired performance, and this detection is conducted using an observable test pattern. For example, in the above-described image recording device, a test pattern is recorded on recording paper, and the density of the test pattern is optically read (see Japanese Laid-open Patent Publication No. 2000-43382).